Field of the Invention
The present invention relates to a driving apparatus, a lithography apparatus, and a method of manufacturing an article.
Description of the Related Art
Robots, transportation machines, and industrial machines and the like that have movable parts driven under controlled conditions regarding its position are known. When a positioning mechanism of such a driving apparatus breaks down, the driving apparatus has to be stopped long time for recovery efforts such as specification of the failure location and repair/replacement of parts, and the throughput will decrease. Also, the performance may be maintained and managed by providing a mechanism such as a sensor for self-monitoring or self-diagnosis or the like in each unit of a driving apparatus to shorten the down time of the driving apparatus required for recovery efforts. However, parts only for self-diagnosis are redundant for an apparatus and cause cost increase. Therefore, Japanese Patent No. 4272750 discloses an apparatus in which temporal changes in dynamic characteristics of a driving mechanism are identified, and self-diagnosis for maintaining performance is performed. Also, Japanese Patent Laid-Open No. 2003-284388 discloses an apparatus comprising a movable part having a plurality of actuators, wherein a thrust balance of respective actuators is monitored, and an abnormality determination is performed.
However, the apparatus disclosed in Japan Patent No. 4272750 just focuses attention on changes in input-output characteristics of the whole apparatus, and cannot specify a cause of an internal failure of the apparatus. In addition, when identifying dynamic characteristics, although higher-order modeling is needed to improve an accuracy of identification, high-order components are affected by machine differences or noises or the like, and thus, it is not possible to obtain data with high accuracy. Also, the apparatus disclosed in Japanese Patent Lain-Open No. 2003-284388 just detects whether or not abnormality exists in a driving mechanism, and cannot perform specification of failure spots and quantitative acquisition of failure states.